Recently, Millimeter Wave technology and Massive Multi-Input Multi-Output (MIMO) technology have been considered to be a part of the critical technology of 5G in the future, and have attracted wide attention from academia and industry. The frequency band of millimeter wave has a large amount of available spectrum resources and can meet the increasing traffic demand of mobile communications. In addition, due to the short wavelengths of millimeter waves, according to antennatheories, the antenna size of millimeter wave systems may also be small, so that it is possible to place hundreds of or even thousands of antennas in a small space, which is more advantageous for the application of large-scale antenna technology in real systems. Further, a beamforming technology provided by large-scale antennas can effectively compensate for the shortcomings of large path fading of millimeter wave channels, and provides the possibility for applying millimeter-wave technology to mobile communications.